The packaging of MEMS components has several different functions. The packaging protects the component from mechanical and chemical environmental influences. In addition, the type of packaging or housing determines how the component may be installed and contacted at the site of use. In this regard, housings for surface mounting technology (SMT) installation are of particular importance. In the case of a MEMS microphone component, the housing also takes over a portion of the microphone functionality, since the acoustic connection as well as the back-side volume of the microphone diaphragm are largely determined by the design of the housing. Therefore, the housing has a significant influence on the transmission characteristics of a MEMS microphone.
United States Published Patent Application No. 2009/0180655 A1 discusses a microphone package of the type mentioned at the outset. The microphone package includes a MEMS microphone component having a housing composed of a housing base and a housing cover. The housing base and housing cover are connected to one another in a pressure-tight manner, and thus enclose the back-side volume of the microphone component, which is mounted on the housing base. Sound is conducted to the microphone diaphragm from below. For this purpose, the microphone component is mounted in a pressure-tight manner above the exit opening of an access channel in the housing base. Sound is introduced via a tubular connector in the housing cover which opens into the access channel in the housing base.
This design requires a specially produced, relatively thick housing base, which as a whole is comparatively costly. In addition, in this case good microphone performance may be ensured only if the entry opening and the exit opening of the access channel as well as the vertical extension of the access channel are relatively large. As a result, the options for miniaturizing the known microphone package are limited.